The present invention generally relates to a large-sized parasol, such as a beach parasol and a garden parasol, and in particular to a ratchet based control mechanism for opening/closing the large-sized parasol.
Large-sized umbrellas or parasols, such as garden parasols and beach parasols, are usually equipped with a handle or handwheel for operating a rope-based driving mechanism to open/close a canopy of the parasol. The large-sized parasol usually comprises a central rod along which a runner is movably mounted. A crown is attached to a top end of the central rod. Ribs extend from the crown for supporting the canopy. Stretchers extend from the runner and pivoted to the ribs whereby by moving the runner along the central rod, the ribs are caused to move toward/away from the central rod and thus opening/closing the canopy. A rope that is manually wound/unwound by means of the handle has an end attached to the runner whereby winding/unwinding the rope moves the runner along the central rod.
For the large-sized parasols, the torque required to rotate the handle is quite large, causing manual operation thereof to be difficult. A disadvantage is that during the process of winding the rope to open the canopy, an operator must from time to time maintain the required torque to ensure smooth opening of the parasol. Devices for temporarily retaining the rope during the winding process are available in the market. Such devices allow an operator to be temporarily released from maintaining the required torque by himself or herself. However, such devices are very complicated and thus expensive. In addition, such devices are not able to provide a stepwise operation which ensures proper progress of winding the rope by the operator.
It is thus desirable to provide a large-sized parasol having a stepwise control device for winding/unwinding a rope thereof in order to overcome the above discussed problems.
Accordingly, an object of the present invention is to provide a control device for opening/closing a large-sized parasol, the device comprising a ratchet based mechanism consisting of a ratchet wheel and a pin cooperating with ratchet wheel to control the opening/closing operation in a stepwise fashion.
Another object of the present invention is to provide a control device for a large-sized parasol comprising a mechanism for generating consecutive impact sounds during opening the parasol for indication of proper operation.
A further object of the present invention is to provide a control mechanism for opening/closing a large-sized parasol, the control mechanism having a simple structure and thus low costs.
To achieve the above objects, in accordance with the present invention, there is provided a parasol control mechanism comprising a shaft rotatably received in aligned holes defined in a central rod of the parasol. A handle is coupled to a first end of the shaft for manually rotating the shaft. A rope is fastened to the shaft whereby when the shaft is rotated, the rope is wound to/unwound from the shaft for opening/closing the parasol. A ratchet wheel defines a central bore tightly fit over the shaft whereby a friction is present between the ratchet wheel and the shaft. A block is attached to the rod and defines a bore for rotatably supporting the shaft. A blind hole is defined in the block with a spring biased pin received in the blind hole. A free end of the pin engages with the teeth of the ratchet for generating consecutive impact sounds when the shaft is rotated in a first direction to open the parasol. When the shaft is rotated in an opposite second direction to close the parasol, the ratchet wheel is prevented from rotation by the pin. With a sufficient large torque applied to the shaft, the friction is overcome and the shaft is rotated in the second direction to release the rope for closing the parasol.